Division of Radiation Oncology, China Medical University Hospital, Taichung City, Taiwan.
PLoS One. 2013 May 16;8(5):e64665. doi: 10.1371/journal.pone.0064665. Print 2013.
Respiratory motion causes uncertainties in tumor edges on either computed tomography (CT) or positron emission tomography (PET) images and causes misalignment when registering PET and CT images. This phenomenon may cause radiation oncologists to delineate tumor volume inaccurately in radiotherapy treatment planning. The purpose of this study was to analyze radiology applications using interpolated average CT (IACT) as attenuation correction (AC) to diminish the occurrence of this scenario. Thirteen non-small cell lung cancer patients were recruited for the present comparison study. Each patient had full-inspiration, full-expiration CT images and free breathing PET images by an integrated PET/CT scan. IACT for AC in PET(IACT) was used to reduce the PET/CT misalignment. The standardized uptake value (SUV) correction with a low radiation dose was applied, and its tumor volume delineation was compared to those from HCT/PET(HCT). The misalignment between the PET(IACT) and IACT was reduced when compared to the difference between PET(HCT) and HCT. The range of tumor motion was from 4 to 17 mm in the patient cohort. For HCT and PET(HCT), correction was from 72% to 91%, while for IACT and PET(IACT), correction was from 73% to 93% (*p<0.0001). The maximum and minimum differences in SUVmax were 0.18% and 27.27% for PET(HCT) and PET(IACT), respectively. The largest percentage differences in the tumor volumes between HCT/PET and IACT/PET were observed in tumors located in the lowest lobe of the lung. Internal tumor volume defined by functional information using IACT/PET(IACT) fusion images for lung cancer would reduce the inaccuracy of tumor delineation in radiation therapy planning.
呼吸运动导致 CT 或正电子发射断层扫描（PET）图像上肿瘤边缘出现不确定性，并导致 PET 和 CT 图像配准时出现失准。这种现象可能导致放射肿瘤学家在放射治疗计划中不准确地勾画肿瘤体积。本研究旨在分析使用插值平均 CT（IACT）作为衰减校正（AC）的放射学应用，以减少这种情况的发生。本比较研究共招募了 13 例非小细胞肺癌患者。每位患者均进行了吸气相、呼气相 CT 扫描和自由呼吸 PET 扫描。使用 PET 中的 IACT（IACT）进行 AC 以减少 PET/CT 失准。应用低剂量辐射的标准化摄取值（SUV）校正，并将其肿瘤体积勾画与 HCT/PET（HCT）的进行比较。与 PET（HCT）和 HCT 之间的差异相比，IACT 与 PET（IACT）之间的失准度降低了。在患者队列中，肿瘤运动范围从 4 到 17 毫米不等。对于 HCT 和 PET（HCT），校正范围从 72%到 91%，而对于 IACT 和 PET（IACT），校正范围从 73%到 93%（*p<0.0001）。对于 PET（HCT）和 PET（IACT），SUVmax 的最大和最小差异分别为 0.18%和 27.27%。在肺癌中，使用 IACT/PET（IACT）融合图像定义的功能信息来确定肿瘤内部体积，这将减少肿瘤勾画在放射治疗计划中的不准确性。
